Methods have been developed for engineering molecular architectures based on the principles of self-assembly and self-organization. Self-assembly (SA) can be realized by hydrogen-bonding, coordination chemistry, .pi.--.pi. interactions and Van der Waals forces. Self-organization produces such diverse structures as liquid crystals, micelles self-assembly monolayers and Langmuir-Blodgett (LB) films. The LB film technique denotes monolayers and multilayers transferred from the water-air interface onto a solid substrate and offers relatively rapid construction with Angstrom (.ANG.) level control of supramolecular assemblies of amphiphilic molecules where the resulting architecture depends on the shape and charge distribution of the molecules from which they are made. The LB and SA film techniques are reviewed in two books: Langmuir-Blodgett Films, Ed. by Gareth Roberts (1990) Plenum Press, N. Y.; and, An Introduction to Ultrathin Organic Films: from Langmuir-Blodgett to Self-Assembly, by Abraham Ulman (1991) Academic Press, Boston.
The LB ultra thin film method is particularly well suited for fabricating a variety of organically-based opto-electronic devices and in particular, integrated optical structures. Such applications necessitate: (1) that the optical component of the desired characteristic be incorporated into an amphiphilic molecule; (2) that a sufficient multilayer film thickness for proper device functioning be achieved and; (3) that the multilayer assembly satisfies any required arrangement of the functional opto-electronic component.
A relevant example of the LB film technique being utilized to construct an optical device is provided by 2.sup.nd -order non-linear optical (NLO) materials useful for second harmonic generation (SHG) in optical wave guided structures. For LB device fabrication, one needs first to prepare from the organic NLO material an amphiphilic molecule. Next, a multilayer film thickness of approximately 1 micron (em) for a wave guide structure, must be successfully deposited. And finally, the required arrangement for SHG of a non-centrosymmetric disposition of the polar NLO constituents, has to be achieved.